1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) used in a surveying instrument or the like. In particular, the present invention relates to an LCD in which information can be displayed while maintaining the contrast of an LCD plate regardless of the ambient temperature of the LCD plate, and also relates to an LCD in which information can be certainly indicated regardless of the ambient temperature of the LCD plate.
2. Description of the Related Art
Since LCD's can be made light and thin and have low power consumption, they have been used in various information indicating apparatuses. For instance, in surveying instruments, such as a light wave distance-measuring meter or an electronic theodolite, an LCD is used to indicate operation instructions or measurements to an operator.
A plate of the LCD is composed of a glass substrate which includes a liquid crystal enclosed therein. When the polarization state of light passing through the liquid crystal changes, the LCD plate selectively permits light to pass therethrough or interrupts light to indicate information as the contrast of the light which is represented by darkness or brightness of the segments.
Surveying instruments are generally used outdoors where the possibility of a large change in temperature exists thus resulting in the possibility that the characters on the LCD become difficult to read.